THE EFFECT OF VARIOUS BASE CORE MATERIALS ON THE SETTING OF A POLYVINYL SILOXANE IMPRESSION MATERIAL/

Five resin-modified glass ionomers and amalgam, used as a base or core buildup material, were clinically evaluated for whether they effected polymerization of a low viscosity (light body) regular set polyvinyl siloxane impression material. A total of 20 samples per group was prep ared according to the manufacturer's recommendations. Ten samples from each group were handled with latex gloves during mixing and the other 10 were handled with vinyl gloves. Five of the 10 samples had the out er surface prepared with a round diamond wheel. impressions were made of all the samples. The impression materials were visually scored inhi bited or noninhibited. Inhibited impression materials met at least one following criterion: (1) an oily substance on the surface of the impr ession readily collected on a sterile explorer tine as it was moved ac ross the impression surface; (2) a rippled appearance on the surface o f the impression material; or (3) unpolymerized impression material ad herent to the prepared sample surface. If none of the criteria were ob served, the impression was scored noninhibited. The data were analyzed with the chi square analysis (level of significance p = 0.05). Total chi square analysis revealed a significant difference between brands ( p = 0.0001) and between prepared and non-prepared samples (p = 0.001). Interrater reliability data were analyzed with the kappa correlation analysis. Raters were in complete agreement (kappa = +1). The prepared samples of Vitrebond material had an inhibitory effect on the polymer ization of Express impression material.